SPC and Upton are saying that this could be a pretty nice outbreak of severe weather not only in uptons area but north into new england. Isolated Tornado threat is even in play although the biggest threat is wind with any clusters that form.

...THERE IS A SLGT RISK OF SVR TSTMS FROM THE UPPER OH VALLEY AND MID ATLANTIC STATES INTO NEW ENGLAND...

...SYNOPSIS... AN UPPER TROUGH CURRENTLY EXTENDING SWD THROUGH THE GREAT LAKES AND ANCHORED BY A VORTEX OVER HUDSON BAY WILL UNDERGO FURTHER AMPLIFICATION AS A SHORTWAVE TROUGH TRACKS ESEWD FROM THE UPPER GREAT LAKES TO NY/PA THIS FORECAST PERIOD. AT 12Z SUNDAY...A COLD FRONT ATTENDANT TO THE PARENT LONGWAVE TROUGH SHOULD EXTEND SWWD FROM SRN ONTARIO THROUGH THE LOWER OH VALLEY TO CENTRAL AR AND WWD INTO OK. THIS BOUNDARY WILL PROGRESS E/SEWD MOVING THROUGH MUCH OF THE NERN AND MID-ATLANTIC STATES...AND EXTEND WSWWD INTO THE CENTRAL GULF COAST STATES BY 12Z MONDAY.

FARTHER W...AN IMPULSE EMANATING FROM AN UPPER LOW ALONG THE NRN CA COAST IS EXPECTED TO MOVE INTO WRN/NRN MT THIS AFTERNOON AIDING IN SOME TSTM DEVELOPMENT OVER THE HIGHER TERRAIN. MEANWHILE...HEIGHT RISES ARE EXPECTED ACROSS THE NRN HIGH PLAINS...TENDING TO LIMIT TSTM DEVELOPMENT.

...MID-ATLANTIC STATES TO NEW ENGLAND... 00Z NAM/GFS AND 12Z ECMWF AGREE WITH THE TIMING OF THE COLD FRONT TODAY...REACHING NRN NY TO WRN PA/UPPER OH VALLEY DURING THE EARLY-MID AFTERNOON. GIVEN THE TIMING OF THE FRONT ALLOWING FOR SURFACE HEATING/DESTABILIZATION AND THE ARRIVAL OF FORCING ALOFT DURING THE AFTERNOON/EVENING...THE FORECAST CONFIDENCE REMAINS GOOD FOR THE DEVELOPMENT OF SEVERE STORMS TODAY INTO TONIGHT ACROSS THE SLIGHT RISK AREA. SWLY LOW LEVEL WINDS ACROSS THE OH VALLEY TO WRN PA AND SSWLY LOW LEVEL WINDS IN LEE OF THE CENTRAL APPALACHIANS TO THE HUDSON VALLEY/NEW ENGLAND WILL EACH SUPPORT MOISTURE ADVECTION INTO THESE REGIONS. ALTHOUGH MIDLEVEL LAPSE RATES ARE FORECAST TO BE MODEST /AOB 6.5 C PER KM/ ACROSS THE SLIGHT RISK AREA...SURFACE HEATING COMBINED WITH THE MOISTURE RETURN WILL RESULT IN MODERATE INSTABILITY FROM MD/D.C./DELMARVA TO SERN/ERN NY AND SWRN NEW ENGLAND THIS AFTERNOON. MLCAPE ACROSS THIS CORRIDOR WILL BE UP TO 1500-2000 J/KG WHILE FURTHER W OVER THE UPPER OH VALLEY VALUES WILL BE UP TO 1000 J/KG.

DIFFLUENT FLOW ALOFT AND HEIGHT FALLS WITH THE APPROACH OF THE UPPER GREAT LAKES SHORTWAVE TROUGH...AND CONVERGENCE/ASCENT ALONG THE COLD FRONT AND PRE-FRONTAL/LEE TROUGH EXTENDING FROM VA TO ERN NY WILL SUPPORT TSTM DEVELOPMENT BY EARLY-MID AFTERNOON IN VICINITY AND AHEAD OF THESE SURFACE BOUNDARIES. STRENGTHENING WIND FIELDS AND EFFECTIVE BULK SHEAR OF 40-50 KT COMBINED WITH THE AVAILABLE INSTABILITY WILL SUPPORT ORGANIZED STORMS. SHEAR VECTORS MORE NORMAL TO THE LEE TROUGH SUGGEST A GREATER POTENTIAL FOR DISCRETE STORMS...INCLUDING SUPERCELLS. VERTICALLY VEERING WINDS AND HIGHER THETAE EXTENDING FROM MD/ERN PA TO SERN NY/SWRN NEW ENGLAND SUPPORT AN ISOLATED TORNADO THREAT ALONG WITH DAMAGING WINDS AND HAIL. FARTHER W INTO THE UPPER OH VALLEY...ORGANIZED STRONG TO SEVERE STORMS WILL BE POSSIBLE BY EARLY-MID AFTERNOON WITH STRONG WIND GUSTS AND HAIL THE PRIMARY THREATS.

ALTHOUGH INSTABILITY SHOULD BE WEAKENING THIS EVENING...A FURTHER INCREASE IN DEEP LAYER WIND FIELDS INTO THE NERN STATES AND 60-90 METER HEIGHT FALLS ACROSS THIS REGION SHOULD COMPENSATE THE WEAKER THERMODYNAMICS FOR AT LEAST A CONTINUED THREAT FOR DAMAGING WINDS INTO PARTS OF NEW ENGLAND. FORECAST SOUNDINGS SUGGEST A TORNADO CANNOT BE RULED OUT ACROSS SRN NEW ENGLAND AS STRENGTHENING SLY LLJ SUPPORTS AN INCREASE IN LOW LEVEL HODOGRAPH CURVATURE.

...WV/VA/CAROLINAS SWWD TO TN/CENTRAL GULF COAST STATES... A MIDLEVEL SHORTWAVE TROUGH...CURRENTLY MOVING ACROSS IL/IND TO THE MID SOUTH PER WATER VAPOR IMAGERY...IS EXPECTED TO WEAKEN TODAY AND MOVE TOWARD THE SRN HALF OF THE APPALACHIANS /WRN VA TO NRN GA/NERN AL/. ASCENT WITH THIS FEATURE COMBINED WITH MODERATE INSTABILITY SHOULD SUPPORT TSTM DEVELOPMENT FROM THE TN VALLEY/NRN EXTENT OF THE CENTRAL GULF COAST STATES INTO THE WRN CAROLINAS AND VA. THE FOCUS FOR GREATER STORM COVERAGE IS UNCERTAIN AT THIS TIME..AND THUS WILL MAINTAIN LOW SEVERE PROBABILITIES.

...NRN HIGH PLAINS INTO SRN SD/NRN NEB... A SURFACE FRONT WILL MOVE SWD TODAY REACHING THE VICINITY OF THE SD/NEB BORDER. SLY LOW LEVEL WINDS S OF THIS BOUNDARY WILL RETURN MOISTURE NWD BENEATH A PLUME OF STEEP LEVEL LAPSE RATES/EML SPREADING EWD INTO SD/NEB. ALTHOUGH MODELS ARE INDICATING MODERATE INSTABILITY FROM NEB/WRN SD INTO PARTS OF THE ADJACENT NRN HIGH PLAINS ALONG WITH STRONG EFFECTIVE BULK SHEAR...HEIGHT RISES ACROSS THIS REGION AND LACK OF SUFFICIENT FORCING ALOFT SUGGEST TSTM DEVELOPMENT SHOULD BE MINIMAL. THIS OUTLOOK WILL MAINTAIN A LOW PROBABILITY FOR SEVERE STORMS...GIVEN THE FAVORABLE INSTABILITY/SHEAR...BUT CONFIDENCE IN GREATER STORM/SEVERE COVERAGE REMAINS LOW.

..PETERS/SMITH.. 08/21/2011

CLICK TO GET WUUS01 PTSDY1 PRODUCT

NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1300Z CURRENT UTC TIME: 1212Z (8:12AM), RELOAD THIS PAGE TO UPDATE THE TIME

.SHORT TERM /NOON TODAY THROUGH 6 AM MONDAY/...UPR LOW SPINNING OVER HUDSON BAY WITH THE JET APPROACHING THE NRNGREAT LAKES PER WATER VAPOR. H25 U COMPONENT WINDS AND H5 HEIGHTANOMALIES WITH THIS SYSTEM ABOUT 2-3 STD/S. 00Z SUITE OF MODELSCONTINUE TO PROG SCT TSTMS DEVELOPING THIS AFTN ACROSS THEW...EVOLVING INTO WIDESPREAD TSTMS THIS EVE AND THRU THE OVERNIGHTAS THE COLD FRONT AND INCREASING DYNAMICS CATCH UP. THIS SOLN HASBEEN ACCEPTED FOR THE FCST.

PARAMETERS REMAIN IN PLACE FOR A SEVERE OUTBREAK. 00Z NAM CAME INA BIT HIGHER WITH THE BRN...RESULTING IN A TENDENCY TOWARDSMULTICELLULAR. SYNOPTIC LLVL DIRECTIONAL SHEAR ISLIMITED...HOWEVER AS STORMS DEVELOP ALLOWING FOR LLVLINFLOW...EXPECT THIS SHEAR TO BE ENHANCED RESULTING IN ANENVIRONMENT MORE SUPPORTIVE OF SUPERCELLS.

ALTHOUGH THERE ISN/T A WARM FRONT INVOF THE CWA WITH THISEVENT...EHI STILL IN THE 1-2 RANGE SUPPORTING A TOR POTENTIAL.INFLOW MAY ENHANCE THESE NUMBERS AS WELL BUT COMPUTATION IS BASEDON SRH SO CONFIDENCE NOT AS HIGH AS IN THE BRN. ANY OUTFLOWBOUNDARIES WILL ELEVATE THE SPIN UP RISK...AND AS THE CONVECTIONCONSOLIDATES TONIGHT THE RISK COULD SHIFT TO LI WITH COASTALBOUNDARY DEVELOPMENT.

PW/S STILL ON TRACK TO REACH JUST UNDER 2 INCHES SO HVY RAIN HASBEEN INCLUDED IN THE FCST. SEE HYDRO SECTION FOR ADDITIONAL INFO.

Hmmm, TWC's hour-by-hour forecast doesn't show precip coming in until 1:45PM or so; up until then it's "mostly cloudy" - meaning at least SOME sun. The other thing it means is that we won't have a round of non-severe convection come through early and hamper instability. We should have at least some heating. Temps are generally on the rise, as it's sitting at 73 right now, and was 71 last I checked. On the hour-by-hour; the hours of 4, 5, and 6 PM are all inside a red box marked severe, and it just says "strong storms'.

If things go the way they seem to be going, this might be the first time a frontal passage like this hasn't been marred by early convection.

I hope this (not so) little cell that just hit me directly is a predictor of what to expect today. Because, my friends, we just had the overall most impressive storm of the summer. Was strong, not severe; but it contained impressive winds, heavy rain, and some very loud thunder. The cell with the hail core missed me, but what we did get was impressive enough; sort of like the type of weather you'd expect during a tropical storm/depression.

And considering I wasn't expecting anything before noon, it was a nice surprise.

Edit: And, it looks like the sun is coming back out; to make things nice for later on!

TRENDS ARE BEING MONITORED FOR AN INCREASING SEVERE THREAT THAT COULD REQUIRE ONE OR MORE WATCHES DURING THE 17-19Z TIME FRAME.

BENEATH DIFLUENT UPPER FLOW DOWNSTREAM OF A VIGOROUS SHORT WAVE TROUGH NOW TURNING EASTWARD THROUGH THE GREAT LAKES REGION... SCATTERED THUNDERSTORM ACTIVITY IS ONGOING THROUGH MUCH OF THE NORTHEAST. ASSOCIATED CLOUD COVER AND PRECIPITATION ARE SLOWING BOUNDARY LAYER DESTABILIZATION IN BROAD POCKETS...COMPLICATING THE SEVERE WEATHER POTENTIAL...WITH SOUTHWESTERLY DEEP LAYER MEAN FLOW AND SHEAR STILL SOMEWHAT MODEST ACROSS MUCH OF THE REGION.

IT DOES APPEAR ONE AREA OF FORCING FOR ASCENT ASSOCIATED WITH A SMALLER SCALE IMPULSE/WEAK AREA OF MID-LEVEL HEIGHT FALLS IS BEGINNING TO SHIFT EAST NORTHEAST OF THE CENTRAL APPALACHIANS. THIS COULD SUPPORT INCREASING STORM DEVELOPMENT WITHIN THE NEXT FEW HOURS ACROSS NORTHERN VIRGINIA INTO PARTS OF SOUTH CENTRAL/ SOUTHEAST PENNSYLVANIA...WHERE STRONGEST SURFACE HEATING IS OCCURRING. LATEST RUC GUIDANCE SUGGESTS INHIBITION FOR MOIST BOUNDARY LAYER PARCELS CHARACTERIZED BY 70F+ SURFACE DEW POINTS IS DIMINISHING...AND MIXED LAYER CAPE COULD EXCEED 2000 J/KG TOWARD THE 18-20Z.

THEREAFTER...THE SEVERE WEATHER POTENTIAL...INCLUDING THE RISK FOR ISOLATED SUPERCELLS AND ORGANIZED STORM CLUSTERS...APPEARS LIKELY TO GRADUALLY INCREASE THROUGH THE REMAINDER OF THE AFTERNOON. THIS PROBABLY WILL INCLUDE AREAS FROM THE LEE OF THE LOWER GREAT LAKES EASTWARD INTO NEW ENGLAND...BUT IT REMAINS UNCLEAR WHETHER THE THREAT WILL BECOME WIDESPREAD...OR REMAIN RELATIVELY LOCALIZED ACROSS THESE AREAS.

Another cell trying to fire up along the same path the last one took. The cells to the north of me are training, looks like our batch of cells is trying to copy them.

Not only have I already seen my best storm this season, it's beginning to look like this will be the first day this year that mutiple cells go through my area. And we're not even in the thick of it yet.

This cell not as intense as the last, as it lacks wind. However, lightning and thunder is more impressive. The thunder sounds like those nuclear explosions they show in those bomb test documentaries on TV.

This cell not as intense as the last, as it lacks wind. However, lightning and thunder is more impressive. The thunder sounds like those nuclear explosions they show in those bomb test documentaries on TV.

Rain coming down REAL hard.

it looks like the storm is just sitting on top of your area and developing even more.

it looks like the storm is just sitting on top of your area and developing even more.

It came in as a moderate rain shower, and just exploded into a blossom of red on radar. It looked like it was weakening as it came in, and then BAM! I just came inside from watching it rain harder than I can remember in recent memory. And the thunder was crazy. This has already been an awesome day for me after the way the entire summer was going storm wise. And according to the forecasts, the bad stuff isn't even here yet; this is only round one.

The Schenectady, NY anti-storm bubble has burst today; in a dramatic fashion. It is now raining down on us, hard.

Edit: And it didn't have any gust front to it, probably because it developed out of nowhere. There was essentially no wind during the entire storm. Looks like it's clearing up a bit now, as the sun is shining through the clouds. Which just helps things out for late this afternoon into this evening.